moniteur d'environnement spatial

CONT: SEM : Le moniteur d'environnement spatial (mesure de l'énergie des flux de particules).

CONT: The SEM subsystem consists of four instruments used for in situ measurements and monitoring of the near-earth (geostationary altitude) space environment and for observing the solar X-ray output. An energetic particles sensor (EPS) and high energy proton and alpha detector (HEPAD) monitor the incident flux density of protons, alpha particles, and electrons over an extensive range of energy levels. Solar output is monitored by an X-ray sensor (XRS) mounted on an X-ray positioning platform, fixed on the solar array yoke. Two redundant three-axis magnetometers, mounted on a deployed 3-meter boom, operate one at a time to monitor Earth's geomagnetic field strength in the vicinity of the spacecraft. The SEM instruments are capable of ground command-selectable, in-flight calibration for monitoring on-orbit performance and ensuring proper operation.
CONT: The Space Environment Monitor (SEM) measures in situ the effect of the Sun on the near-earth solar-terrestrial electromagnetic environment, providing real-time data to the Space Environment Services Center (SESC). The SESC, as the nation's ""space weather"" service, receives, monitors, and interprets a wide variety of solar-terrestrial data, and issues reports, alerts and forecasts for special events such as solar flares or geomagnetic storms. This information is important to the operation of military and civilian radio wave and satellite communication and navigation systems, as well as electric power networks, and to the mission of geophysical explorers, Shuttle and Space Station astronauts, high-altitude aviators, and scientific researchers.